1 /* 2 * Copyright (C) 2001-2003 Sistina Software (UK) Limited. 3 * 4 * This file is released under the GPL. 5 */ 6 7 #include "dm.h" 8 9 #include <linux/module.h> 10 #include <linux/init.h> 11 #include <linux/blkdev.h> 12 #include <linux/bio.h> 13 #include <linux/slab.h> 14 15 #define DM_MSG_PREFIX "linear" 16 17 /* 18 * Linear: maps a linear range of a device. 19 */ 20 struct linear_c { 21 struct dm_dev *dev; 22 sector_t start; 23 }; 24 25 /* 26 * Construct a linear mapping: <dev_path> <offset> 27 */ 28 static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv) 29 { 30 struct linear_c *lc; 31 unsigned long long tmp; 32 33 if (argc != 2) { 34 ti->error = "Invalid argument count"; 35 return -EINVAL; 36 } 37 38 lc = kmalloc(sizeof(*lc), GFP_KERNEL); 39 if (lc == NULL) { 40 ti->error = "dm-linear: Cannot allocate linear context"; 41 return -ENOMEM; 42 } 43 44 if (sscanf(argv[1], "%llu", &tmp) != 1) { 45 ti->error = "dm-linear: Invalid device sector"; 46 goto bad; 47 } 48 lc->start = tmp; 49 50 if (dm_get_device(ti, argv[0], lc->start, ti->len, 51 dm_table_get_mode(ti->table), &lc->dev)) { 52 ti->error = "dm-linear: Device lookup failed"; 53 goto bad; 54 } 55 56 ti->private = lc; 57 return 0; 58 59 bad: 60 kfree(lc); 61 return -EINVAL; 62 } 63 64 static void linear_dtr(struct dm_target *ti) 65 { 66 struct linear_c *lc = (struct linear_c *) ti->private; 67 68 dm_put_device(ti, lc->dev); 69 kfree(lc); 70 } 71 72 static int linear_map(struct dm_target *ti, struct bio *bio, 73 union map_info *map_context) 74 { 75 struct linear_c *lc = (struct linear_c *) ti->private; 76 77 bio->bi_bdev = lc->dev->bdev; 78 bio->bi_sector = lc->start + (bio->bi_sector - ti->begin); 79 80 return 1; 81 } 82 83 static int linear_status(struct dm_target *ti, status_type_t type, 84 char *result, unsigned int maxlen) 85 { 86 struct linear_c *lc = (struct linear_c *) ti->private; 87 88 switch (type) { 89 case STATUSTYPE_INFO: 90 result[0] = '\0'; 91 break; 92 93 case STATUSTYPE_TABLE: 94 snprintf(result, maxlen, "%s %llu", lc->dev->name, 95 (unsigned long long)lc->start); 96 break; 97 } 98 return 0; 99 } 100 101 static struct target_type linear_target = { 102 .name = "linear", 103 .version= {1, 0, 1}, 104 .module = THIS_MODULE, 105 .ctr = linear_ctr, 106 .dtr = linear_dtr, 107 .map = linear_map, 108 .status = linear_status, 109 }; 110 111 int __init dm_linear_init(void) 112 { 113 int r = dm_register_target(&linear_target); 114 115 if (r < 0) 116 DMERR("register failed %d", r); 117 118 return r; 119 } 120 121 void dm_linear_exit(void) 122 { 123 int r = dm_unregister_target(&linear_target); 124 125 if (r < 0) 126 DMERR("unregister failed %d", r); 127 } 128